JP2005242747A - Data backup system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data backup system in which recovery time is shortened. <P>SOLUTION: The data backup system connected to a magnetic disk device 110 and a host computer 100 and capable of backing up data stored in the magnetic disk device 110 is provided with the magnetic disk device 110 including a differential data storage part 112 for storing differential data within the lapse of a first prescribed period and a data storage part 113 for storing all data in each lapse of a second prescribed period, and a backup device including a full backup data storage part 123 for backing up the data stored in the data storage part 113 and a differential backup data storage part 122 for backing up the differential data stored in the differential data storage part 112, and constituted so as to quickly recover data from the differential backup data storage part 122 and/or the full backup data storage part 123 depending on a fault. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data backup system that backs up data of a host computer in a computer system, and more particularly to a data backup system that can restore data in a short time when a system failure occurs.

  In general, a computer system includes a host computer that performs data processing and an internal or external storage device such as a magnetic disk device that is connected to the host computer and stores data, and data stored in the magnetic disk device when a system failure occurs. A backup device is connected to prevent the loss of data.

  The backup device according to this prior art generally has a full backup function for backing up all data stored in the magnetic disk device on a holiday when the system pauses for the outside, and the full backup within a limited time such as a weekday night. A differential backup function that backs up the difference from the backup, for example, the full backup function is executed on Sundays, and the differential backup function is executed on weekdays at night.

In addition, as a document describing the technology related to the backup system as described above, for example, the following patent document can be cited.
JP-A-11-212875

  The backup system configured as described above restores the full backup data to a magnetic disk device when restoring data when any failure occurs, and then stores the differential backup data that has been differentially backed up to the magnetic disk device. It was meant to be restored.

  More specifically, as shown in FIG. 9, a full backup 91 of all data 90a of the magnetic disk device is performed, and differential data is generated by performing the business operation 92, and a differential backup 93 of only this differential data 90b is created. In the case where a failure 94 occurs after performing the above operation, it is necessary to restore the full backup data 90c subjected to the full backup 91 to the magnetic disk device and further restore the differential backup data subjected to the differential backup 93. For example, the restoration of all the data 90a that has been fully backed up due to the occurrence of a failure only in the differential data 90b is performed even though it is not originally necessary. That is, the backup system according to the prior art has a problem that the recovery time of the system becomes redundant because restoration of full backup data and restoration of differential backup data are always performed at the time of restoration.

  An object of the present invention is to eliminate the above-mentioned problems caused by the prior art, and to provide a data backup system capable of restoring data in a computer system in a short time in accordance with the occurrence of a system failure. .

In order to achieve the above object, the present invention is a data backup system connected to a host computer and a magnetic disk device for storing data of the host computer, and for backing up the data of the magnetic disk device, which stores data A magnetic disk device including a data storage unit and a differential data storage unit that stores data for which a write command has been issued from a host computer within the first predetermined period (differential backup period); A full backup data storage unit that stores data stored in the data storage unit of the magnetic disk device every time a long second predetermined period (full backup period) elapses, and differential data stored in the differential data storage unit A backup device including a differential backup data storage unit for storing For example,
Storing the difference data stored in the difference data storage unit in the data storage unit, and storing the difference data storage unit in the difference data storage unit during a full backup operation executed every second predetermined period; Sequentially performing the step of erasing the difference data and the step of storing the data stored in the data storage unit in the full backup data storage unit of the backup device,
A first feature is that a step of storing the difference data stored in the difference data storage unit in the difference backup data storage unit of the backup device is executed during the differential backup operation executed every first predetermined period. .

  Furthermore, the present invention is characterized in that, in the data backup system, the magnetic disk device erases the differential data stored in the differential data storage unit. The data backup system according to the first feature has a magnetic disk device. The third feature is that the differential data stored in the differential backup data storage unit of the backup device is restored to the differential data storage unit of the magnetic disk device. In the data backup system of the first feature, the magnetic disk device includes: The fourth feature is that the full backup operation and the differential backup operation are performed at the same time. In the data backup system according to the first feature, the magnetic disk device stores data in a full backup data storage unit of the backup device. Squirrel in the data storage A fifth characteristic that the A.

  The data backup system according to the present invention recovers by recovering by recovering the differential data storage unit by recovering / recovering the differential data storage unit by recovering the differential data storage unit and recovering by restoring the data storage unit by simultaneous restoration of the differential data storage unit. By selectively executing, the system can be recovered in a short time.

Hereinafter, an embodiment of a backup system according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining a system configuration of a backup system according to an embodiment of the present invention. FIG. 2 is a diagram for explaining operations in response to a write request and a read request from a host of the backup system according to the present embodiment. 3 is a diagram for explaining the operation at the time of full backup according to the present embodiment, FIG. 4 is a diagram for explaining the operation at the time of differential backup according to the present embodiment, and FIG. 5 is a recovery operation by clearing the differential data of the magnetic disk device. FIG. 6 is a diagram for explaining the recovery operation by restoration of the differential data storage unit of the magnetic disk device, and FIG. 7 is the recovery operation by restoration of the differential data storage unit and the data storage unit of the magnetic disk device. FIG. 8 is a diagram for explaining the recovery operation by restoring the data storage unit of the magnetic disk device. It is a diagram for.
<Configuration>

  First, as shown in FIG. 1, the backup system according to the present embodiment is connected to a host computer 100, a magnetic disk device 110 for storing data of the host computer 100, and the magnetic disk device 110, and the magnetic disk device. And a backup device 120 that backs up data 110. In this example, an example in which the magnetic disk device 110 is connected to the outside of the computer system 110 is shown, but this magnetic disk device 110 is a built-in magnetic disk device built in the host computer 100. Also good.

The magnetic disk device 110 according to the present embodiment includes a data storage unit 113 that stores all data for a predetermined period (full backup period) of the host computer 100 and a predetermined period (differential backup period) within the predetermined period. The difference data storage unit 112 that stores the difference data in the memory and the control unit 111 that controls the storage units 112 and 113, and the backup device 120 stores the data stored in the data storage unit 113 of the magnetic disk device 110. A full backup data storage unit 123 that performs backup of the difference data, a differential backup data storage unit 122 that performs backup of differential data stored in the differential data storage unit 112, and a control unit 121 that controls the storage units 122 and 123. It is configured.
<Write / read request operation>

  Since the magnetic disk device according to the present embodiment includes the data storage unit 113 and the differential data storage unit 112 as described above, it can also be called a differential separation type magnetic disk device. As shown in FIG. When a write request is issued (step 21), the data for which the write request has been made is stored in the differential data storage unit 112 of the magnetic disk device 110, for example, the data and the specified write address. If there is data at the designated address in the unit 112, operation is performed so that new data is overwritten on the existing data at the address (step 22). That is, the magnetic disk device 110 according to the present embodiment updates only the data stored in the differential data storage unit 112 without updating the data in the data storage unit 113 when a write request is issued from the host side. Works like this.

  When a read request is issued from the host computer 100 (step 23), the magnetic disk apparatus determines whether or not data corresponding to the designated address is stored in the differential data storage unit 112 (step 23). 24) When it is determined that the data is stored, the corresponding data is read from the differential data storage unit 112 and transferred to the host (steps 25 to 27). When it is determined that the data is not stored, the data storage unit The corresponding data is read from 113 and transferred to the host (steps 26 to 27).

That is, the backup system according to the present embodiment stores data in the differential data storage unit 112 in response to a write request, and data stored in the differential data storage unit 112 or data corresponding to the differential data storage unit 112 in response to a read request. If the data is not stored, the data is read from the data storage unit 113 and returned to the host.
<Full backup operation>,

  As shown in FIG. 3, the backup system according to the present embodiment includes a step (step 31) in which the magnetic disk device 110 interrupts a write request from the host computer 100 when a full backup request 30 is issued from the host side. A step of recording all data stored in the difference data storage unit 112 at a corresponding address of the data storage unit 113 (step 32) and a step of clearing (erasing) all the data stored in the difference data storage unit 112 (step 33). ), The step of resuming the reception of the write request from the host side interrupted in step 31 (step 34), and the backup of all data stored in the data storage unit 113 to the full backup data storage unit 123 of the backup device 120 Are sequentially executed.

That is, in the backup system according to the present embodiment, when a full back request is issued, the magnetic disk device 110 overwrites the data in the difference data storage unit 112 on the data storage unit 113 and then the full backup data storage unit in the backup device 120. It operates so as to perform backup to be saved in 123. Note that this full backup takes a long time to perform backup of all data, and is executed, for example, on Sundays every week.
<Differential backup>

  In the backup system according to the present embodiment, as shown in FIG. 4, when a differential backup request 40 is issued from the host side, the magnetic disk device 110 interrupts the write request from the host computer 100 (step 41), A step of recording all data and addresses stored in the differential data storage unit 112 in the differential backup data storage unit 122 (step 42), and a step of resuming acceptance of a write request from the host side interrupted in step 41 ( Step 44) is executed sequentially.

  That is, in the backup system according to the present embodiment, when a differential backup request is issued, the magnetic disk device 110 performs differential backup in which the data in the differential data storage unit 112 is saved in the differential backup data storage unit 122 of the backup device 120. To work. Note that this differential backup is executed at night every weekday, for example.

As described above, in the backup system according to the present embodiment, the magnetic disk device includes the differential data storage unit 112 and the data storage unit 113, and writes using the differential data storage unit 112 in response to a write request from the host side. When the full backup request is made, the data of the differential data storage unit 112 is transferred to the data storage unit 113 and then the full backup data storage unit 123 of the backup device 120 is operated to perform backup of all data, It operates so as to restore (recover) data from the backup device 120 to the magnetic disk device 110 in accordance with the timing of failure occurrence described below.
<Recover operation 1>

  First, as shown in FIG. 5B, it is assumed that “full backup” − “differential backup” − “differential backup” − “full backup” is performed and a failure occurs before the next “differential backup”. .

  In this case, since the backup system according to the present embodiment performs recovery 50 by clearing (erasing) the differential data storage unit 112 of the magnetic disk device 110 as shown in FIG. A process of interrupting the write request (step 51), a process of erasing the data in the differential data storage unit 112 of the magnetic disk device 110 after the interruption (step 52), and from the host computer 100 interrupted in the step 51 The step of restarting the read and write requests (step 53) is sequentially executed.

As a result, the backup system according to the present embodiment, when a failure such as data deletion due to data deletion / virus or the like after the latest full backup occurs, deletes writing after the latest full backup, so the latest full backup immediately before is deleted. Since it is possible to return to the backup state and only the data in the differential data storage unit 112 is deleted, the system can be recovered in a short time.
<Recover operation 2>

  Next, as shown in FIG. 6B, a case is assumed in which a failure occurs after several “differential backups” are performed.

  In this case, since the backup system according to the present embodiment performs recovery 60 by restoring the differential data storage unit 112 of the magnetic disk device 110 as shown in FIG. 6A, first, read and write requests from the host computer 100 are made. The step of interrupting (step 61) and the step of recovering the difference data stored in the differential backup data storage unit 122 of the backup device 120 by overwriting the differential data storage unit 112 of the magnetic disk device 110 after the interruption (step 61) 62) and the step of resuming the read / write request from the host computer 100 interrupted in step 61 (step 63).

As a result, the backup system according to the present embodiment can return to the previous differential backup state when the failure occurs between differential backups, and only writes data in the differential data storage unit 112. Can be performed in a short time.
<Recover operation 3>

  Next, as shown in FIG. 7B, after performing “full backup” and several “differential backups”, it becomes necessary to return to the “differential backup” state before “full backup” for some reason. Assuming that

  In this case, the backup system according to the present embodiment performs recovery 70 by restoring the differential data storage unit 112 and the data storage unit 113 of the magnetic disk device 110 as shown in FIG. A step of interrupting the read / write request (step 71), and after this interruption, recovering the differential data stored in the differential backup data storage unit 122 of the backup device 120 by overwriting in the differential data storage unit 112 of the magnetic disk device 110 Step (step 72), recovering the full data stored in the full backup data storage unit 123 of the backup device 120 by overwriting the data storage unit 113 of the magnetic disk device 110 by overwriting (step 73), and the step 71 interrupted at 71 DOO read and write requests to resume the process from the computer 100 (step 74) and sequentially executed. The execution order of the steps 72 and 73 is arbitrary and may be simultaneous.

As a result, when the backup system according to the present embodiment needs to return to the “differential backup” state before the previous “full backup”, the system is recovered at high speed using both backup data stored in the backup device 120. be able to.
<Recover operation 4>

  Next, as shown in FIG. 8B, a case is assumed where data in the data storage unit 113 of the magnetic disk device 110 is lost due to a hardware failure or the like.

  In this case, as shown in FIG. 8A, the backup system according to the present embodiment first interrupts the read and write requests from the host computer 100 in order to recover the data storage unit 113 (step 81). After the interruption, a step of recovering the full data stored in the full backup data storage unit 123 of the backup device 120 by overwriting the data storage unit 113 of the magnetic disk device 110 by overwriting (step 82); The step of restarting the read and write requests from the interrupted host computer 100 (step 83) is sequentially executed.

  As a result, the backup system according to the present embodiment recovers the full data at the time of the previous full back from the full back data up storage unit 123 even if the data storage unit 113 of the magnetic disk device 110 has lost data, Since the write data after the full backup is stored in the differential data storage unit 112, the system can be recovered easily and in a short time.

  As described above, the data recovery system according to the present embodiment has a data area to be stored in the magnetic disk device, the data storage unit 113 for storing data at the time of the full backup operation, and a write command after the full backup operation. It is divided into the differential data storage unit 112 that stores the differential data, the storage area of the backup device 120 is also divided into the full backup data storage unit 123 and the differential backup data storage unit 122, and the magnetic disk device 110 performs a difference during the full backup operation. The differential data stored in the data storage unit 112 is overwritten in the data storage unit 113 and then the backup is performed in the full backup data storage unit 123 of the backup device 120. During the differential backup operation, the differential data storage unit 112 is operated. The data stored in By operating as back up to click updater storage unit 122 can perform the recovery of the system at high speed in response to the timing / conditions failure.

  The data backup system of the present invention is effective for a computer system that performs full backup and differential backup. For example, daily differential backup for daily business data such as financial institutions, securities companies, life insurance companies, accounting systems, etc. This is effective for all computer systems that perform all backups at regular intervals such as units.

The figure for demonstrating the system configuration | structure of the backup system by one Embodiment of this invention. FIG. 5 is a diagram for explaining operations in response to a write request and a read request from a host in the backup system according to the present embodiment. The figure for demonstrating the operation | movement at the time of full backup by this embodiment. The figure for demonstrating the operation | movement at the time of the differential backup by this embodiment. The figure for demonstrating the recovery operation | movement by the difference data clear of a magnetic disc unit. The figure for demonstrating the recovery operation | movement by the restoration of the difference data storage part of a magnetic disc unit. The figure for demonstrating the recovery operation | movement by the restoration of the difference data storage part and data storage part of a magnetic disc device. The figure for demonstrating the recovery operation | movement by the restoration of the data storage part of a magnetic disc unit. The figure for demonstrating the data backup method by a prior art.

Explanation of symbols

100: host computer, 110: magnetic disk device, 111: control unit, 112: differential data storage unit, 113: data storage unit, 120: backup device, 121: control unit, 122: differential backup data storage unit, 123: full Backup data storage unit.

Claims (5)

A data backup system connected to a host computer and a magnetic disk device for storing data of the host computer, and for backing up data of the magnetic disk device,
A magnetic disk device including a data storage unit for storing data, and a differential data storage unit for storing data for which a write command has been issued from the host computer within the first predetermined period;
A full backup data storage unit that stores data stored in a data storage unit of the magnetic disk device every time a second predetermined period that is longer than the first predetermined period is stored in the differential data storage unit A backup device including a differential backup data storage unit for storing the differential data,
The magnetic disk device is
During a full backup operation executed every second predetermined period,
Storing the difference data stored in the difference data storage unit in the data storage unit;
Erasing the difference data stored in the difference data storage unit;
Sequentially storing the data stored in the data storage unit in the full backup data storage unit of the backup device;
At the time of differential backup operation executed every first predetermined period,
A data backup system for executing a step of storing differential data stored in the differential data storage unit in a differential backup data storage unit of a backup device. 2. The data backup system according to claim 1, wherein the magnetic disk device erases the difference data stored in the difference data storage unit. The data backup system according to claim 1, wherein the magnetic disk device restores the differential data stored in the differential backup data storage unit of the backup device to the differential data storage unit of the magnetic disk device. 2. The data backup system according to claim 1, wherein the magnetic disk device simultaneously performs the full backup operation and the differential backup operation. 2. The data backup system according to claim 1, wherein the magnetic disk device restores data in a full backup data storage unit of the backup device to the data storage unit.

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